1. Field of the Invention
The present invention relates to a numeric controller of a rotating mechanism for rotating a rotor around a predetermined rotation axis by a driving source linearly moving along a predetermined linear axis through a nonlinear transmission mechanism.
2. Description of Related Art
Conventionally, a rotating mechanism having a driving source for linear movement and a transmission mechanism for transmitting the linear movement of the driving source to a rotor is known for a machine tool having rotating mechanism for rotating a rotor around a predetermined rotation axis. A rack and pinion mechanism, worm gear mechanism etc. are used as the transmission mechanism.
Some of the rotating mechanism uses a cam mechanism for driving the rotor, which is, for example, shown in a rotating mechanism of Japanese Patent Publication Laid-open No. Hei 10-43976 (Japanese Patent Application No. Hei 8-198035).
FIG. 4(A) shows a conventional rotating mechanism.
A rotating mechanism 1 has rotors 12 rotatably supported by a base member 11, a driving source 13 for rotating the rotors 12, and a transmission mechanism 14 for transmitting a movement of the driving source 13 to the rotors 12.
The rotors 12 are rotatably supported by the supporting shaft 15 around a rotation axis A, and a recessed portion 121 for engaging later-described connecting shaft 143 is formed at an end thereof.
A built-in motor type spindle head 122 is provided adjacent to the rotation axis A of the rotor 12, the spindle head 122 rotating in accordance with the rotating movement of the rotor 12 for conducting various processing to a workpiece.
The driving source 13 has a servo motor 131, a pinion gear 132 for engaging a gear provided at a distal end of a rotation axis of the servo motor 131, a feed screw rod 133 being rotated by the pinion gear 132 in accordance with rotation of the rotation axis of the servo motor 131, and a feed nut 134 for engaging the feed screw rod 133 to move linearly along an extending direction of the feed screw rod 133.
The transmission mechanism 14 for transmitting the linear movement of the feed nut 134 of the driving source 13 to the rotor 12 includes a horizontal slider 141, a vertical slider 142 and a connecting shaft 143.
The horizontal slider 141 is movable along an extending direction of a horizontal guide 111 linearly provided onto the base member 11. A vertical guide 141A extending perpendicular to extending direction of the horizontal guide 111 is provided on an upper surface of the horizontal slider 141.
The vertical slider 142 is movable along the extending direction of the vertical guide 141A, and the connecting shaft 143 for engaging to the recessed portion 121 of the rotor 12 is provided on an upper surface thereof.
The feed nut 134 of the driving source 13 is attached and fixed to the right horizontal slider 141.
Incidentally, the horizontal sliders 141 respectively provided to the two rotors 12 are mutually connected by a connecting rod 144 so that one of the rotors 12 is rotated in accordance with the rotation of the rotor on the right side in FIG. 4(A).
The rotating mechanism 1 is operated as follows.
(1) The feed screw rod 133 is rotated by the pinion gear 132 when the servomotor 131 is driven.
(2) The feed nut 134 is moved along the extending direction of the feed screw rod 133 by the rotation of the feed screw rod 133.
(3) The horizontal slider 141 is moved simultaneously with the movement of the feed nut 134 and the rotor 12 is rotated through the connecting shaft 143.
Incidentally, the connecting shaft 143 maintains engagement with the recessed portion 121 of the rotor 12 by moving along the vertical guide 141A together with the vertical slider 142 during movement of the horizontal slider 141.
And, as shown in FIG. 4(B), a locus 12A of the rotor 12 is arc-shaped around the rotation axis A in .theta. direction relative to a locus 134A of the feed nut 134 in L direction.
According to the rotating mechanism 1, the linear movement of the driving source 13 can be transmitted to the rotation of the rotor 12 by a simple movement of the horizontal slider 141 and the vertical slider 142 along the guide 111 and 144A.
Therefore, no wear of meshed portion, which causes failure of rotation movement as in the rack and pinion mechanism and worm gear mechanism, can occur, thereby obtaining highly durable rotating mechanism.
Further, when a plurality of rotor 12 is disposed adjacently in the transmission mechanism such as the rack and pinion mechanism, disposition space has to be set large for the gears of the adjacent transmission mechanism not to interfere with each other. In contrast thereto, since the rotor 12 can be closely disposed adjacently according to the above-mentioned rotating mechanism 1, a size of a machine tool having a plurality of rotor can be reduced.
For controlling drive of the rotating mechanism 1 by a numeric controller, the actually controlled driving source 13 moves linearly. Accordingly, a linear position L of the driving source 13 is calculated based on angular position .theta. of the target rotor 12 and the linear position L is transmitted to the numeric controller as a command value.
However, what is ultimately necessary for a process to give command to the numeric controller is angular position of the rotor 12 of the rotating mechanism. Therefore, the angular position .theta. of the rotor 12 is conveniently given to the numeric controller for constructing a software program, which reduces burden on programmers.